GB2035260A

GB2035260A - Spring operated re-wind mechanism

Info

Publication number: GB2035260A
Application number: GB7937255A
Authority: GB
Original assignee: Barnes Group Inc
Current assignee: Barnes Group Inc
Priority date: 1978-11-06
Filing date: 1979-10-26
Publication date: 1980-06-18
Also published as: BR7907154A; ES251433U; CA1147221A; FR2440905A1; IT7927007A0; DE2944801A1; ES485700A1; GB2035260B; ES251433Y; US4261437A; NL7908075A; IT1124903B; MX152821A

Description

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GB 2 035 260 A

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SPECIFICATION

Spring operated re-wind mechanism

5 This invention relates broadly to spring operated re-wind mechanisms which are used in a great variety of domestic, industrial and power plant applications such, for example, as pull cord engine starters, hose reels, vacuum cord reels and the like, 10 and it will be described in this specification in connection with a pull cord type engine starter mechanism.

Starter mechanisms of the pull cord type for use with mowers, outboard marine engines and the like 15 are conventionally provided with a re-wind mechanism for returning the pull cord and its pulley to their at-rest positions, and known devices of this type almost universally use a spiral power spring as the means for providing the re-winding energy. Atypical 20 re-wind mechanism is disclosed in the United States patent to Mack No. 2,564,787, and it will be seen that it includes a spiral power spring which in its normal operative position is in a spiral configuration positioned adjacent an annular retainer for the spring. 25 Operation of the pull cord in such a mechanism causes the spring to be at least partially wound down on the central shaft from its normal position, thus storing energy which is utilized on release of the pull cord to re-wind the cord on its pulley and 30 return the parts to condition for another start.

In addition to the spiral power spring another spiral spring is available commercially under the trademark Spirator and is described and claimed in the United States patents to Foster Nos. 2,833,027 35 and 2,833,534. This spring is background in its normal condition and throughout its entire range of operation, being normally in engagement with and bearing outwardly against a cylindrical retainer and being wound down onto a central shaft to store 40 energy which is delivered upon return of the spring to its normal condition. This type of spring can produce much greater energy than the power spring but it is unstable in all conditions and requires special handling, and forthis reason its use in 45 re-wind mechanisms has not been proposed as it has been assumed that such would not be possible without danger to persons installing the springs or servicing the motors, or to users.

It has therefore been the principal object of this 50 invention to provide a spring operated re-wind mechanism which incorporates a backwound spring but is provided in a configuration which is not only safe to handle but permits easy and quick installation and replacement.

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Description of the drawings

Figure 1 is an end view of an internal combustion engine showing the re-wind mechanism provided by the invention in connection with a pull cord type of 60 starter;

Figure 2 is an enlarged sectional view taken on line 2-2 of Figure 1;

Figure 3 is an exploded view showing the parts of the re-wind mechanism, and 65 Figure 4 is a perspective view of a spring cartridge as provided by the invention.

A pull cord re-wind mechanism as provided by the invention is illustrated in the drawings in association with an internal combustion engine 2 having a crankshaft 4, which may have utility as the driving means for any stationary or mobile unit such, for example among the latter category, as mowers, outboard motors and the like.

The re-wind mechanism and its associated parts comprises a housing 10 which is connected to the motor by bolts or the like and which may be dome shaped. A shaft 12 extends centrally and inwardly of the housing toward and in axial alignment with the crankshaft 4. the inner surface of the housing surrounding the shaft 12 is formed as an open cylindrical recess 14, the wall 16 of which surrounds and is concentric with the housing shaft 12. A groove or recess 18 extends radially, tangentially or otherwise outwardly from the recess 14 into material of the housing which surrounds and defines the recess.

Spring means of a novel form for re-winding mechanisms are provided by the invention and comprise a spring cartridge which takes the form of a hollow cylindrical casing 20 the thickness and diameter of which are such, in the mechanism being described, that it may be snugly received within the recess 14. In its preferred form, which is shown in Figure 4, the casing has an annular wall 22, a side wall 24 having a central opening 28 therein which is concentric with the annularwall 22 ofthe casing and through which the housing shaft 12 extends when the spring cartridge is in the recess 14 and the parts are assembled. Side wall 24 and the annular wall 22 are preferably formed integrally from a single piece of synthetic plastic or other suitable material providing a cup shaped casing. A tang 30 projects radially outwardly from the annularwall of the casing and is ofthe same size and shape as the radial groove 18 so that when the casing is positioned within the recess 14 the tang is snugly received within the groove and prevents rotation ofthe casing with respect to the housing.

Within the casing 20 there is positioned and held a back-wound spiral spring 40 which is constructed and operable in the manner described in the Foster patents referred to above. The outer convolution of the spring is permanently held and restrained in its normal backwound condition by the annularwall 22 and the side wall 24 ofthe casing, and the inner part ofthe spring extends in an open spiral configuration toward and to the centre ofthe casing 20. The outer end ofthe spring has a turned-back part 42 which is snugly received within a right-angle shaped slot 44 in the annularwall ofthe casing to connect the outer end ofthe spring to the casing, and the inner end of the spring is turned into a circle or other shape to provide an abutment 46 which is positioned within the central opening 28 ofthe casing.

A pull-cord assembly is provided in the re-wind apparatus being described and comprises a pulley 50 having a deep radial groove to the interior of which there is connected the inner end of a pull cord 52 the outer end of which is provided with a handle. The pulley is provided with two central hubs 54,56 which extend axially outwardly from the opposite

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GB 2 035 260 A

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side faces ofthe pulley. Hub 54 extends from one side face ofthe pulley toward the spring cartridge and through the central opening 28 in the cartridge and is hollow and surrounds and is journaled on the 5 housing shaft 12. On its outer surface and positioned within the spring 40 the outer surface of hub 54 is provided with a radially extending surface 58 which provides an abutment positioned adjacent the abutment 46 on the inner end ofthe spring. The second 10 hub 56 extends from the other side face of the pulley toward the crankshaft 4 and is axially aligned therewith and is provided with means 58 which engage the crankshaft during the starting cycle of the motor.

15 The spring cartridge comprising the casing 20 with its exterior radial tang 30 and the backwound spring within the casing and connected at its outer end to the casing, with its inner end abutment 46 within the central opening ofthe casing, forms a unitary 20 package which may be handled without danger from the spring, and which may be dropped into the housing recess 14 with the tang in groove 18, after which the pulley, spring cartridge and housing 10 may be attached to the motor for starter operation. It 25 will be apparent that the spring cartridge may be removed and replaced at any time without difficulty or danger. In a preferred form ofthe invention the cartridge has the single side wall 24 with the central opening 28 in it, but it may have two side walls for 30 certain installations, and in either case the casing with the spring within it provides a stable assembly which fulfills all ofthe requirements ofthe invention.

It will be understood that in order to cause the spring to re-wind the pull cord at least part ofthe 35 backwound spring must be wound down onto the pulley hub 54 and that this is accomplished by engagement ofthe pulley hub abutment 58 with spring abutment 46 followed by further rotation of the pulley. The spring abutment must, of course, be 40 moved in the proper direction to wind the spring down, and this requires that the spring cartridge be properly placed within the housing recess 14 in order to properly present the spring abutment to the hub abutment. While this may be done by observa-45 tion, means are provided by the invention for facilitating this placement, and this is done by differentiation ofthe two sides of the spring cartridge. This is accomplished, of course, by the cartridge described above which has a closed and an 50 open side wall. Another means comprises the provision of a spring cartridge having two side walls which are of different appearance, as by making one side wall ofthe cartridgefrom opaque material and the other side wall from transparent material. In 55 either case proper placement will be achieved by placing the cartridge in the housing recess with a pre-determined side up.

While this specification has described a spring operated re-wind mechanism for an engine starting 60 apparatus, it will be understood that the invention is useful with, and applicable to, any other spring operated re-wind mechanism having a fixed part, a relatively rotatable part, and a spring in which energy is stored as the parts are moved with respect 65 to each other and which is used to restore the parts to their original condition.

Claims

70 1. A spring operated re-wind mechanism, comprising a fixed part, a cylindrical casing positioned in engagement with the fixed part and having a central opening therein, means preventing relative rotation between the fixed part and the casing, a backwound 75 spiral spring within the casing and bearing on the inner surface of its cylindrical wall and having an outer end adjacent the cylindrical wall and having an abutment on its inner end position within the central opening ofthe casing, means connecting the outer 80 end ofthe spring to the cylindrical wall ofthe casing, and a rotatably mounted shaft extending into the central opening ofthe casing and having an abutment thereon positioned to engage the abutment on the inner end ofthe spring when the shaft is rotated. 85
2. A spring operated re-wind mechanism according to claim 1, in which the fixed part has a circular recess formed therein of substantially the same diameter as the cylindrical casing, and the casing is positioned within the recess.

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3. A spring operated re-wind mechanism according to claim 2, in which the means for preventing relative rotation between the fixed part and the casing comprises a groove extending from the peripheral wall ofthe recess into the material ofthe 95 fixed part, and an outwardly extending tang on the periphery of the casing extending into the groove and having substantially the same dimensions as the groove.
4. As a new article of manufacture, a spring 100 cartridge for a re-wind mechanism comprising a cylindrical casing having a peripheral wall and at least one side wall and having a central opening which is concentric with the peripheral wall, a backwound spiral spring within the casing with its 105 outer convolution bearing againstthe peripheral wall ofthe casing and connected thereto, and the inner end ofthe spring having an abutment formed thereon which is positioned within the central opening in the casing.

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5. The new article of manufacture according to claim 4, having only one side wall.
6. The new article of manufacture according to claim 4, having two side walls.
7. The new article of manufacture according to 115 claim 6, in which the two side walls are respectively formed of materials having different appearances.
8. The new article of manufacture according to claim 6, in which one ofthe side walls is formed of opaque material and the other is formed of transpa-

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9. The new article of manufacture according to claim 4, having a tang connected to the peripheral wall and extending outwardly therefrom.
10. A spring operated rewind mechanism, com-125 prising a housing having a circular recess therein, a fixed shaft connected to the housing and extending therefrom concentrically into the recess, a cylindrical spring cartridge casing within the recess and having a peripheral wall and at least one side wall and a 130 central opening concentric with the peripheral wall

and surrounding the housing shaft, a projection extending radially outwardly from the peripheral wall ofthe spring cartridge casing and engaging the housing to prevent relative rotation between the 5 cartridge and the housing, a backwound spiral spring within the cartridge casing with its main body engaging and bearing outwardly against the peripheral wall ofthe casing and having its outer end fixed to the peripheral wall ofthe casing and its inner 10 end provided with an abutment normally positioned within the central opening ofthe casing, rotatable means mounted adjacent the casing and having a hub extending through the central opening in the casing and rotatably mounted on the housing shaft, 15 an abutment on the hub positioned to engage the abutment on the inner end ofthe spring when the rotatable means is rotated, the direction of wind of the spring and the relative positions ofthe abutment on the hub ofthe and the abutment on the inner end 20 ofthe spring being such that when the hub is rotated the spring is at least partly wound down to the hub from its normal position adjacent the peripheral wall ofthe casing.
11. A spring operated re-wind mechanism sub-25 stantially as described herein with reference to and as illustrated in the accompanying drawings.

Printed for Her Majesty's Stationery Office by Croydon Printing Company Limited, Croydon Surrey, 1980.

Published by the Patent Office, 25 Southampton Buildings, London, WC2A1 AY,

from which copies may be obtained.